The NS, or Name Server records of a domain, reveal which servers handle the Domain Name System (DNS) records for it. Setting the name servers of a specific host company for your domain address is the simplest way to direct it to their system and all its sub-records are going to be handled on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), etc, so if you want to edit any one of these records, you will be able to do it through their system. In other words, the NS records of a domain name reveal the DNS servers that are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to obtain the DNS records of the Internet domain you want to reach. In this way the website that you're going to see is going to be retrieved from the proper location. The name servers typically have a prefix “ns” or “dns” and each domain name has at least two NS records. There isn't any practical difference between the two prefixes, so which one a hosting provider will use depends completely on their preference.